Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 66 (5), 437-42

The CB2-preferring Agonist JWH015 Also Potently and Efficaciously Activates CB1 in Autaptic Hippocampal Neurons

Affiliations

The CB2-preferring Agonist JWH015 Also Potently and Efficaciously Activates CB1 in Autaptic Hippocampal Neurons

N Murataeva et al. Pharmacol Res.

Abstract

The G protein coupled receptors CB(1) and CB(2) are targets for the psychoactive constituents of cannabis, chief among them Δ(9)-THC. They are also key components of the multifunctional endogenous cannabinoid signaling system. CB(1) and CB(2) receptors modulate a wide variety of physiological systems including analgesia, memory, mood, reward, appetite and immunity. Identification and characterization of selective CB(1) and CB(2) receptor agonists and antagonists will facilitate understanding the precise physiological and pathophysiological roles of cannabinoid receptors in these systems. This is particularly necessary in the case of CB(2) because these receptors are sparsely expressed and problematic to detect using traditional immunocytochemical approaches. 1-Propyl-2-methyl-3-(1-naphthoyl)indole (JWH015) is an aminoalkylindole that has been employed as a "CB(2)-selective" agonist in more than 40 published papers. However, we have found that JWH015 potently and efficaciously activates CB(1) receptors in neurons. Using murine autaptic hippocampal neurons, which express CB(1), but not CB(2) receptors, we find that JWH015 inhibits excitatory postsynaptic currents with an EC50 of 216nM. JWH015 inhibition is absent in neurons from CB(1)(-/-) cultures and is reversed by the CB(1) antagonist, SR141716 [200nM]. Furthermore, JWH015 partially occludes CB(1)-mediated DSE (∼35% remaining), an action reversed by the CB(2) antagonist, AM630 [1 and 3μM], suggesting that high concentrations of AM630 also antagonize CB(1) receptors. We conclude that while JWH015 is a CB(2)-preferring agonist, it also activates CB(1) receptors at experimentally encountered concentrations. Thus, CB(1) agonism of JWH015 needs to be considered in the design and interpretation of experiments that use JWH015 to probe CB(2)-signaling.

Figures

Fig. 1
Fig. 1
JWH015 potently and efficaciously inhibits excitatory neurotransmission via CB1. (A) Structure of JWH015. (B) Sample EPSC time–course showing inhibition by JWH015 [2 μM] and reversal by the CB1 antagonist SR141716 (SR1) [200 nM]. Inset shows sample EPSC traces at time-points indicated by A, B, and C. (C) Concentration–response curve for JWH015 in wild-type (squares), GPR55 knock-out neurons (diamond), and CB1 knock-out neurons (triangle).
Fig. 2
Fig. 2
JWH015 inhibits EPSCs via a presynaptic site of action. (A) Graph shows paired-pulse ratios under control conditions (circles) and following treatment with JWH015 (triangles). (B) Sample EPSC pairs under control and after JWH015 treatment. Scale bars: 1 nA, 5 ms.
Fig. 3
Fig. 3
The “CB2-selective” antagonist AM630 also antagonizes CB1. (A) Sample EPSC time–course showing inhibition by JWH015 [2 μM] and reversal by the CB2-preferring antagonist AM630 [10 μM]. Inset shows sample EPSC traces at time-points indicated by A, B, and C. (B) Bar graph showing relative EPSC charge after treatment with JWH015 [2 μM] either on its own or with SR141716 [200 nM], AM630 [2 μM] or AM630 [10 μM]. *p < 0.05, **p < 0.01, one-way ANOVA vs. JWH015. (C) Bar graph showing relative EPSC charge after DSE (3-s depolarization) and/or treatment with AM630 [10 μM] in CB1−/− or wild-type mice. There are no statistically significant differences between the treatments.
Fig. 4
Fig. 4
AM630 attenuates and JWH015 occludes DSE. (A) Depolarization–response curve shows relative EPSC inhibition with increasing durations of depolarization, under control conditions and following AM630-treatment [1 μM] and [3 μM] in wild-type neurons. There is statistically significant difference between each treatment and the control at time points of 500 ms (except for 1 μM), 1 s, 3 s and 10 s. (B) Bar graph shows that AM630 increases the duration of depolarization required for a half maximal response. The treatments differ significantly from control. (C) Bar graph shows percent DSE from a 3 s stimulus that remains after treatment with JWH015 [2 μM] or AM630 [3 μM].
Fig. 5
Fig. 5
JWH015 induces little CB1 receptor desensitization. Depolarization–response curve showing relative EPSC inhibition after increasing durations of depolarization—under control conditions and after over-night treatment with 100 nM JWH015 (triangles) or 1 μM JWH015 (diamonds). The only condition where there was a statistically significant difference from control was with 1 μM JWH015 pretreatment and a depolarization of 3 s (p < 0.05 two-way ANOVA, Bonferroni post hoc test).

Similar articles

See all similar articles

Cited by 15 PubMed Central articles

See all "Cited by" articles

MeSH terms

Feedback